Thread tensioning or braking devices for shuttles



E. GRUNKE July 3, 1962 THREAD TENSIONING OR BRAKING DEVICES FOR SHUTTLES Filed Dec. 2, 1959 F763 FIG. 4

IN VENT'OP rl'd1 GPUN/(E United States Patent 3,042,082 TIEEAD TENSIONING 6R BRAKING DEVICES FUR SHUTTLES Erich Griinlre, Hinwil-Zurich, Switzerland, assignor to Emil Forster, Hinwil-Zurich, Switzerland Filed Dec. 2, I959, er. No. 856,717 4 Claims. Cl. 139-417) The present invention relates to shuttle thread tensioning or braking devices for controlling the unwinding of the thread from shuttles.

Shuttles are well known in which the thread is manually threaded and the tension thereof for controlling unwinding of the thread is effected by devices mounted within the shuttles. Usually either the walls of the thread guide within the shuttle are constructed as brakes, or springs are arranged in the region of the thread guides and operate to retard unwinding of the thread. Apart, however, from the fact that brake shoes acting on both sides of the thread cannot effect uniform braking of unwinding, the known proposals in respect of thread braking for shuttles are inadequate for fulfilling the requirements of the modern textile industry, particularly for the following reasons:

By virtue of factors, such as differences in the thickness of the yarn, the nature and circumference of the twisted yarn, different braking or snapping strengths thereof, it is sometimes necessary to weave with shuttles having no thread braking means, yet when processing other yarn materials it is essential to employ shuttles which are fitted with such means. When the latter proves to be desirable the possibility must be borne in mind when using certain thread thicknesses, both of ensuring unimpeded passage of the thread and of exerting on the thread a tensioning action which may vary in its requirements from strong to weak.

Hitherto it has only been possible to comply with these requirements at the most only in a very primitive and ineffective manner by utilising a large supply of shuttles. Thus it has been customary for a portion of the shuttles required to be kept in stock to be without any device for tensioning the thread, while others have been fitted with adjustable thread brakes. The necessity for maintaining a large stock of shuttles has greatly increased the operating costs of weaving, while the length of time required for the change-over from operating with shuttles without thread brakes to the use of shuttles provided with thread tensioning means additionally leads to appreciable unproductive interruptions of work.

Again the known devices even when provided with means for adjusting the braking action exerted on the thread have not been successful in practice for the reason that said adjustment could not be effected to a sufficiently small degree and, in any case, has only been possible in such constructions of shuttles wherein the thread is manually threaded.

The primary object of the present invention is to overcome these difficulties, i.e. to provide a practical tensioning device which is capable of surmounting the restricted conditions of weaving involving maintaining in stock large numbers of different kinds of shuttles, and which at the same time is applicable to shuttles suitable for automatic as distinct from manual winding of the thread.

Accordingly the present invention is based on the conception that it is possible by a simple conversion to use the same shuttle fitted with a thread brake so that on the one hand the thread brake may be brought into action or rendered wholly inoperative as desired to meet any requirements as they arise, yet While work is proceeding with thread tensioning to obtain a practically infinitely variable adjustment of the braking action by very simple means.

3fl42fi32 Patented July 3, 1962 Generally, the present invention resides in the feature that the thread braking or tensioning means is so constructed and arranged within the shuttle that it is displaceable into and out of a position in which it completely releases the thread, is infinitely adjustable between positions representing zero and mam'mum tensioning effect on the thread, and is fixable in any position of adjustment.

Furthermore in achieving that object of the invention which is to surmount the disadvantages of an excessively coarse adjustment of the braking action and of a complicated construction, the braking device may incorporate a stationary brake shoe and a displaceable spring-loaded brake shoe, of which the latter is adjustable over the entire range of displacement between the position in which it is in contact with the thread brake shoe and the position in which the thread is able to move quite freely, that is to say, with the exception of the contact position the displaceable brake shoe can open up passage of any desired width without involving braking action.

A further feature of the invention resides in that the device is provided with a pin which carries the displaceable brake shoe, the spring producing resilient load for the braking action, and the means for adjusting said load.

Further advantageous constructions reside in the disc form of the brake shoe and the arrangement of notches in the control of the means for adjusting the spring tension. The latter, by means of conventional marking, makes it possible accurately to set and maintain the spring at the desired tension. This is particularly advantageous in the present invention in that it facilitates adjustment of the spring tension independently of the width of the passage for the thread.

Further features of the invention and details of the advantages achieved thereby will be apparent from the following description of one embodiment of the thread brake for shuttles illustrated in the accompanying drawings by way of example and in which:

FIGURE 1 is a diagrammatic plan view of the front part of a shuttle showing the guide thereof and the thread braking or tensioning device.

FIGURE 2 is a transverse section through the thread tensioning or braking device fitted inside the thread guide in the shuttle, but on a much larger scale than that of FIGURE 1.

FIGURE 3 is a side elevation of a detail showing the displaceable brake shoe of FIGURE 2, i.e. viewed in the direction in which resilient loading is applied to it.

FIGURE 4 is a section through the displaceable brake shoe of FIGURE 3.

FIGURE 5 is a side elevation of a lock nut for adjusting the spring tension on the adjustable brake shoe, and

FIGURE 6 is also a side elevation of a clamping ring for securing a set screw adapted to effecting the adjustment of the brake shoes.

In the view of a shuttle shown in FIGURE 1 the pointed end at the front thereof is indicated by a and the thread guide by b. The braking device for the thread unwound from the bobbin e is indicated as a whole by c and is arranged with the guide inside the shuttle.

The path of the thread is shown in the threading position in FIGURE 1. Leaving the bobbin e the thread passes through a groove fin the shuttle to the thread guide b and thence to the braking or tensioning device provided in the region of the thread guide and shown in FIGURE 1 by the reference 0.

The construction and arrangement of the brake or tension device which constitutes the present invention is apparent in detail from FIGURES 2-6, all of which reproduce on a large scale the essential parts for the thread guide. In this respect it will be appreciated that the enlarged section according to FIGURE 2 is a transverse section through the shuttle, i.e. the thread brake is viewed in a plane disposed at an angle of 90 with respect to that of the illustration according to FIGURE 1.

As shown in FIGURE 2 the thread guide which is represented as a whole in FIGURE 1 by the reference b, has side walls 1 and Z. The wall 2 receives an externally threaded and bifurcated pin 3 which is secured to the wall by means of a collar 4 presenting a shoulder on the pin, a washer 5 and a nut 6. An internally threaded cap nut 7 serves on the one hand as a lock nut for the nut 6 and on the other hand houses a set screw 8 which on adjustment is adapted to abut against stop means such as a lock pin 9 which is located in a longitudinal bore 9a in the pin 3. The set screw 8 is secured in its position of adjustment within the cap nut 7 by a resilient clamping ring 10 which is received in an annular groove 11 of the cap nut 7 with one end thereof extending through a bore 12 to press against a disc 13 located in said bore 12, said disc 13 in turn resting on the thread of the set screw 8.

Arranged in the thread passage 14 of the shuttle and mounted on the pin 3 is a displaceable brake shoe 15 the web 16 of which is guided in a longitudinal slot or bifurcation 17 of the pin 3. The inner end of the stop means or lock pin 9 remote from that engaged by the set screw 8 is adapted to contact with the abutment surface or web 16, and such contact is maintained by a conical volute spring 18 which thus resiliently loads the shoe in its position of adjustment determined by the elements 8, 9 and 16. The other end of the spring is of hook form to abut against a lock nut 19 in screw threaded engagement with the pin 3. The lock nut 19 is provided with radial grooves 20 into which the hooked end of the spring 18 engages in extending into the longitudinal slot 17 thereby preventing the lock nut from being displaced after the required adjustment of the spring 18 has been effected. The nut 19 is also provided on its opposite face with recesses 21 for the reception of a spanner when adjustment is required.

The stationary brake shoe between which and the displaceable brake shoe 15 the thread 23 passes, is constituted by an internally dished part 22 of the wall 2 of the thread guide.

By adjusting the screw '8 and thus the inner end of the pin 9 serving as the stop; for the abutment or web 16 of the brake shoe 18 the latter is brought into any desired position of adjustment, e.g. into the position shown in FIGURE 2. In this position either the passage is impeded for a thread of the diameter of the illustrated thread 23 or a thicker thread becomes subjected to a braking or tensionin g action the extent of which can be finally varied by adjusting the nut 19 on the externally threaded pin 3.

Thus a single device according to the present invention is capable of providing either a free passage for the thread or a braking or tensioning action of any desired strength on threads of any diameter and thus is able to comply with all modern operating conditions of use without having to stock an alternative type of device.

It will be appreciated that a thread tensioning device of the present invention is not limited to being fitted between the walls of a thread guide with one of said walls used as a stationary brake shoe. Thus for example the pin 3 may equally well be rceived in a separate brake shoe mounted on a wall of the groove in the shuttle.

In the foregoing, the invention has been described with reference to a specific illustrative device. It will be evident, however, that variations and modifications, as well as the substitution of equivalent elements for those illustrated, may be made without departing from the scope and broader spirit of the invention as set forth in the appended claims. The specification and drawings are accordingly to be regarded in an illustrative rather than in a limiting sense.

I claim:

l. A thread tension device for a loom shuttle comprising as a unitary structure, in combination, a fixed brake shoe mounted on a fixed support in said shuttle and disposed on one side of the thread path within said shuttle, a displaceable brake shoe on said support disposed on the opposite side of said thread path, resilient means on said support in engagement with and urging said displaceable brake shoe toward said fixed brake shoe, means mounted on said support and concentric therewith for infinitely adjusting the position of said displaceable brake shoe and for retaining said displaceable brake shoe in an adjustable position of minimum spacing from said fixed brake shoe, and means movable on said support and concentric therewith for adjusting the pressure of said resilient means independently of the spacing of said displaceable shoe from said fixed shoe.

2. A thread tension device for a loom shuttle comprising as a unitary structure, in combination, a fixed brake shoe mounted on a fixed support in said shuttle and disposed on one side of the thread path within said shuttle, a displaceable brake shoe on said support disposed on the opposite side of said thread path, resilient means on said support in engagement with and urging said displaceable brake shoe toward said fixed brake shoe, means mounted on said support and concentric therewith for infinitely adjusting the position of said displaceable brake shoe and for retaining said displaceable brake shoe in an adjustable position of spacing from said fixed brake shoe, and means movable on said support end concentric therewith for adjusting the pressure of said resilient means independently of the spacing of said displaceable shoe from said fixed shoe, said means for adjusting the position of said brake shoe including adjustable stop means for abutment by a central part of said displacea'ble brake shoe while said resilient means urges an outer part of said displ-aceable brake shoe toward said fixed shoe.

3. A thread tension device for a loom shuttle comprising, in combination, a fixed brfie shoe mounted on pin means supported by said shuttle and disposed on one side of the thread path within said shuttle, supporting means for securing said pin means in fixed position, a displaceable brake shoe in said shuttle disposed on the opposite side of said thread path, means for infinitely adjusting the position of said displaceable brake shoe and for limiting the minimum spacing of said displaceable brake shoe from said fixed brake shoe including a stop means in said pin means and an abutment surface on said displaceable shoe, and independently adjustable resilient means urging said displaceable shoe against said stop means and towards said fixed shoe, said stop means being a displaceable lock pin movable axially of said pin means and said abutment surface being defined by a central web on said displaceable shoe, and said pin means including an externally threaded portion having a longitudinal slot, a nut in threaded engagement with said portion and in abutting relationship with an end of a spring defining said resilient means remote from said displaceable shoe and from said web, and said web being slidable axially of said slot into engagement with said lock pin.

4. A device in accordance with claim 3, wherein said nut has notches on its outer face for the reception of a manually operatable tool and at least one recess on its opposite face for the reception of one end of the spring so as to prevent said spring from turning in any position of relative adjustment of the brake shoe.

References Cited in the file of this patent UNITED STATES PATENTS 

